Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the readOnlyHint annotation, the description adds that results are aggregated, date-range constrained, and grouped by a dimension. It also identifies the HTTP GET method via the endpoint path. It does not mention response shape or pagination, but the aggregation semantics are meaningful additional context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded with the core operation before stating the method. The 'Read-only' clause is somewhat redundant with the readOnlyHint annotation but does not meaningfully bloat the text.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 6-parameter GET endpoint with no output schema, the description conveys the essential aggregation concept needed to understand what the tool returns. The remaining invocation details are well covered by the fully documented schema; minor gaps such as response shape and pagination behavior remain.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already documents all six parameters with formats, defaults, constraints, and the dimension enum. The description's date-range and grouped-by language largely restates the schema's from/to and dimension descriptions, adding no new parameter-level meaning.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific operation: aggregated play analytics for videos, with a date range and grouping dimension. The mention of 'videos' and the GET /analytics/videos/plays endpoint clearly distinguishes it from the live-stream analytics sibling. There is no ambiguity about the target resource.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description clearly indicates this tool is for video play analytics over a date range, which provides enough context to route an agent correctly. It does not explicitly name alternatives or exclusions, but the video-vs-live-stream distinction is obvious from the scope and endpoint.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.